Immersed vertical pump with reduced thrust loading

ABSTRACT

For an immersed pump having a suction port directly immersed in a liquid for operation, the present invention provides a pump that eliminates the need to seal a rotating shaft with a shaft sealing apparatus and that reduces the effect on individual pump sections of a) the thrust of the rotating shaft effected by the rotation of an impeller and b) the weight of a motor acting in the same direction, thereby preventing defects in the pump. 
     To achieve this object, this invention provides an immersed pump configured in such a way that an impeller 7 is driven and rotated by a motor 2 to draw a liquid from a suction port 4A into a pump housing 3A and eject it from an ejection port 5. The suction port 4A is provided at the lower end of a body frame 1 or on the outer circumference of the upper end of the housing 3A, while the ejection port 5 is provided at the lower end of the housing 3A.

FIELD OF THE INVENTION

The present invention relates to an immersed pump having a suction portdirectly immersed in a liquid for operation.

PRIOR ART

Immersed pumps having a suction port immersed in a liquid so as to drawin the liquid have been widely known. As shown in FIG. 4, conventionalimmersed pumps are generally configured so that an impeller 26 mountedat the tip of a rotating shaft 25 is driven and rotated by a motor 21mounted at the upper end of a body frame 20, in order to draw in aliquid from a suction port 23 provided at the lower end of a housing 22at the lower end of the body frame 20. The liquid is then pressurizedand discharged sideward from a ejection port 24 at the upper end of theframe through a channel in the side of the body frame 20.

Since an immersed pump of this type force-feeds a liquid upward, theliquid may leak to the frame 20 through the circumference of the motor'srotating shaft 25. Thus, a shaft sealing apparatus 27 such as amechanical seal must be used to support and seal the rotating shaft 25to prevent leakage. Accordingly, maintenance or replacement of the shaftsealing apparatus 27, which is associated with usage frequency, can beso cumbersome that the lifetime expectancy of the pump decreases.

In addition, since the liquid drawn in from the center of the lower endof the housing 22, pressurized, and ejected sideward from the body frame20, a lateral force may be imparted to the rotating shaft 25 to vibrateand deform it, thereby vibrating the entire pump and creating loudnoise.

Furthermore, since the thrust of the rotating shaft 25 effected by therotation of the impeller 26 acts in the same direction as the weight ofthe motor 21, a large force may be applied to each section of the pump,particularly a bearing which supports the rotating shaft 25 mounted inthe body frame 20, resulting in defects.

DISCLOSURE OF THE INVENTION

It is a technical object of this invention to improve the above immersedpump, by altering its design in such a way that the pump transfers aliquid downward, thereby eliminating the need to seal the shaft with ashaft sealing apparatus—and thus the need for maintenance/replacementassociated with such sealing—and reducing the effect on individual pumpsections of a) the thrust of the rotating shaft effected by the rotationof the impeller and b) the weight of the motor acting in the samedirection. This improved design should provide an immersed pump that canreduce the incidence of defects.

It is another technical object to provide an immersed pump thatprecludes a lateral force caused by the ejected liquid from beingimparted to the rotating shaft, in order to prevent vibration and/ordeformation of the rotating shaft as well as vibrations affecting theentire pump.

To achieve these objects, this invention provides an immersed pumpcomprising a body frame, a motor mounted at the upper end of the bodyframe, a pump housing mounted at the lower end of the body frame, arotating shaft extending from the motor through the inside of the bodyframe to the housing, and at least one impeller attached to the rotatingshaft in the housing, the impeller being driven and rotated by the motorto draw a liquid in a tank from a suction port into the housing andeject it from an ejection port, characterized in that the suction portis provided above the impeller, and in that the ejection port isprovided at the lower end of the housing.

Since the suction port through which a liquid is drawn in is providedabove the impeller installation position so that the liquid drawn intothe housing is force-fed downward, use of a shaft sealing apparatus suchas a conventional mechanical seal can be omitted to eliminate the needfor cumbersome maintenance and replacement of the apparatus.

In addition, the upward thrust of the rotating shaft effected by therotation of the impeller offsets the downward weight of the motor, thusreducing the force imparted to each section of the pump. Consequently,it is possible to prevent defects that may occur in conventional pumpsin which the motor's thrust and gravitational force act in the samedirection.

Furthermore, the liquid drawn into the housing is force-fed downwardtherein, thereby precluding a lateral force from being applied to therotating shaft despite the ejection of the pumped liquid. Thisconfiguration further prevents the rotating shaft from being vibrated ordeformed and avoids vibration of the entire pump that result in noise.

According to the immersed pump described in this invention, the ejectionport is provided on an extension of the axis of the rotating shaft, anda joint that is directly joined with an ejection hole provided at thebottom of the tank is mounted in the ejection port.

Moreover, according to this invention, the housing is formed by couplinga plurality of short, cylinder-shaped housing members together in thevertical direction, and an impeller is provided in each of at least someof the housing members. In this case, the impellers are provided in someof the lower housing members while a suction port is provided on theouter circumference of each of at least some of the remaining upperhousing members.

In addition, desirably, the plurality of housing members are detachablycoupled together, and each of the impellers is remorably attached to therotating shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical sectional front view showing a first embodiment ofthis invention.

FIG. 2 is a vertical sectional front view showing the main feature of asecond embodiment of this invention.

FIG. 3 is a vertical sectional front view showing the main feature of athird embodiment different from the second embodiment.

FIG. 4 is a vertical sectional front view showing a conventionalimmersed pump.

DETAILED DESCRIPTION

FIG. 1 shows a first embodiment of this invention. An immersed pumpaccording to this embodiment comprises a body frame 1, a motor 2 mountedat the upper end of the body frame 1, a pump housing 3A mounted at thelower end of the frame 1, a rotating shaft 6 extending from the motor 2through the frame 1 to the housing 3A, and a plurality of impellers 7provided at the tip of the rotating shaft 6 in the housing 3A.

The body frame 1 fixes the motor 2 and the housing 3A, and comprises amounting frame 1 a mounted on a cover 14 b of the tank 14 for aforce-fed liquid, a hollow portion 1 b provided at the upper end of themounting frame 1 a and having a ventilating opening 12, a plurality ofcolumnar portions 1 c provided at the lower end of the mounting frame 1a, and a dish-shaped housing mounting section 1 d provided at the lowerend of the columnar portion 1 c.

A hole is drilled in the center of the mounting frame 1 a of the bodyframe 1 and the center of the housing mounting section 1 d to allow therotating shaft 6 to be inserted. A bearing 9 allowing the rotating shaft6 to pass rotatably is mounted in the hole in the mounting frame 1 a.

At the same time, the hole in the housing mounting section 1 d isdrilled larger than the diameter of the rotating shaft 6, and theintermediate area between this hole and the rotating shaft 6 constitutesa suction port 4A from which a liquid is drawn into the housing 3Athrough the columnar portion 1 c.

The rotating shaft 6 is formed integrally with the shaft of the motor 2and is supported in the middle of the body frame 1 using a rollingbearing 10 within a motor casing.

The rotating shaft 6 has a fan 11 located in the hollow portion 1 b ofthe body frame 1 to allow heat generated by the rotation of the motor 2to escape through the ventilating opening 12 and to cool the rotatingshaft 6, which is heated by the motor.

The pump housing 3A is composed of a plurality of housing members 3 adetachably coupled together, and of a housing bottom cover member 3 bmounted at the lower end of the housing member 3 a located in the loweststage, and is tightened and fixed to the body frame 1 using a mountingbolt 3 d passed through the bottom-cover member 3 b.

Each housing member 3 a comprises an outer circumferential wall 13 a, apartitioning wall 13 b integrally provided at one end of the outercircumferential wall 13 a to partition each pump chamber, wherein thewalls are each shaped like a short cylinder. Each of the housing membersexcept for the top one possesses on the partitioning wall 13 b a guidevane standing upward and a partitioning plate 13 c provided at the upperend of the guide vane, which are both provided integrally with thepartitioning wall 13 b. Thus, a gap for liquid to flow is formed betweenthe partitioning wall 13 b and the partitioning plate 13 c in such a waythat the guide vanes are able to guide the liquid through the gap.

The partitioning wall 13 b has a suction hole opened at its centerbetween its end and the rotating shaft 6 as well as a seal section 13 dthat seals the intermediate area between the wall 13 b and the impeller7.

In addition, the middle of the partitioning plate 13 c is integratedwith a sleeve 13 e on the rotating shaft 6, and the outer circumferenceof the partitioning plate 13 c is opposed to the inside of the outercircumferential wall 13 a of the adjacent housing member in such a wayas to form a channel between them.

By fitting an end of the outer circumferential wall 13 a on the proximalend of the adjacent outer circumferential wall 13 a, the housing members3 a are coupled together in such a way that their interior surfaces aresealed.

The bottom cover member 3 b comprises in its middle (i.e., on theextension of the rotating shaft 6), an ejection port 5 through which aliquid is ejected downward. The ejection port 5 is directly insertedinto an ejection hole 14 a provided at the bottom of the tank 14 as ajunction and forms a protruding joint 5 a that allows the pump to beinstalled in the tank.

A seal member consisting of a rubber O ring is mounted around the joint5 a of the ejection port 5 to prevent a liquid from leaking from thejunction of the ejection hole 14 a.

Four impellers 7 attached to the tip of the rotating shaft 6 at aspecified interval in such a way as to form stages are arranged in thehousing 3A so as to correspond to the housing members 3 a in therespective stages. The impeller 7 is driven and rotated by the motor 2to draw a liquid from the suction port 4A sequentially into each housingmember 3 a while sequentially force-feeding the drawn liquid to thelower impeller 7 until the drawn liquid is ejected from the ejectionport 5. In this case, the thrust of the rotating shaft 6 effected by therotation of the impeller 7 acts in an upward direction.

The impeller 7 does not need to be provided in all housing members 3 a;it may be provided in only some. The number of impellers 7 is reduced inthis manner to enable the pump's drawing force to be regulated, so eachimpeller 7 is remorably attached to the rotating shaft 6.

Although this embodiment has been described in conjunction with the fourhousing members arranged in the vertical direction, this number can beincreased or decreased as required. In addition, each impeller 7 can beattached to the rotating shaft 6 using an appropriate means, forexample, by inserting keys into respective key grooves provided in aboss of the impeller 7 and in the rotating shaft 6 for fixation, or bytightening screws to fix the impeller.

The immersed pump of this configuration is installed for operation byimmersing the housing 3A in a liquid and joining the ejection port 5with the ejection hole 14 a at the bottom of the tank 14. This mode ofinstallation enables piping for the ejection port 5 to be completed.

During installation, the suction port 4A through which liquid is drawnin is positioned above the impellers 7 provided in the housing 3A, sothat liquid drawn into the housing 3A is force-fed downward.Accordingly, a shaft sealing apparatus such as a conventional mechanicalseal can be omitted, thereby obviating the need for cumbersomemaintenance and replacement of the apparatus.

In addition, the impellers 7 are attached to the rotating shaft 6 sothat the thrust of the rotating shaft 6 acts in an upward direction.Thus, the thrust offsets the downward weight of the motor 2 tosubstantially reduce the force applied to each section of the pump,particularly to the rolling bearing 10 supporting the rotating shaft 6.

As a result, defects that may occur when the thrust and the weight ofthe motor 2 act in the same direction can be prevented.

Moreover, the liquid drawn into the housing 3A is force-fed downward,drawn in through the circumference of the upper end of the housing 3A,and ejected downward from the ejection port 5 provided on the extensionof the axis of the rotating shaft 6. This configuration precludes alateral force effected by the ejected liquid from being applied to therotating shaft 6, thereby preventing the rotating shaft 6 from beingvibrated or deformed while also preventing noises caused by thevibration of the entire pump.

Although this embodiment provides the ejection port 5 on an extension ofthe axis of the rotating shaft 6, this invention is not limited to thisaspect; instead, a plurality of ejection ports may be disposed aroundthe axis in a balanced manner.

In addition, although the first embodiment provides the liquid suctionport 4A at the lower end of the body frame 1, suction ports 4B and 4Cmay be provided on the outer circumferences of the upper ends ofhousings 3B and 3C, respectively, or may be provided at both the upperend of the housing and the lower end of the body frame, as in a secondand a third embodiments, which are shown in FIGS. 2 and 3, respectively.

That is, the housing 3B according to the second embodiment is formed ofthe four housing members 3 a arranged in a vertical direction, with animpeller 7 built into each of the three lower housing members 3 a. Thetop housing member, which is without an impeller 7, is used as a spacer3 c, with the suction port 4B provided in the outer circumferential wall13 a of the spacer 3 c. The housing members in the respective stages aredetachably coupled together.

On the other hand, according to the third embodiment, the impeller 7 isbuilt into each of the two lower housing members 3 a. The two upperhousing members without an impeller 7 are used as the spacers 3 c, withthe suction port 4C provided in each of the spacers 3 c.

The second and third embodiments can be formed of the parts common tothe first embodiment. By determining the numbers of lower housingmembers 3 a and upper spacers 3 c as appropriate in such a way thattheir sum is four or less, the ejection force of the pump can not onlybe adjusted but can also be set to some extent to correspond to thelevel of the liquid in the tank 14.

If, for example, the level of the liquid constantly stored in the tank14 is higher than the housing 3A, the configuration shown in FIG. 1 canbe used. However, to reduce the amount of liquid constantly stored inthe tank 14 and thus the tank's level, one spacer 3 c and three housingmembers 3 a may be provided as in the housing 3B in FIG. 2. To furtherreduce the tank's level, two spacers 2 c and two housing members 3 a maybe provided as in the housing 3C shown in FIG. 3.

In the second and third embodiments, the suction ports 4B and 4C may beporous or meshed.

In addition, the spacer 3 c may be shaped like a simple cylinder withoutthe suction port 4B or 4C.

In these embodiments, a plurality of ejection ports 5 may be disposedaround the axis of the rotating shaft 6 in a balanced manner.

As described above in detail, according to the present immersed pump,the suction port through which a liquid is drawn in is provided abovethe housing so as to force-feed downward a liquid drawn into thehousing, thereby preventing the drawn liquid from being force-fed upwardthrough the circumference of the rotating shaft. Consequently, theconventional shaft sealing apparatus can be omitted to eliminate theneeds for cumbersome maintenance and replacement of this apparatus.

In addition, the upward thrust of the rotating shaft effected by therotation of the impeller offsets the downward weight of the motor toreduce the force applied to each section of the pump, thereby preventingdefects that may occur in conventional pumps because the thrust and theweight of the motor act in the same direction.

Moreover, the liquid drawn into the housing is force-fed downward topreclude a lateral force effected by the ejected liquid from beingapplied to the rotating shaft 6, thereby preventing the rotating shaftfrom being vibrated or deformed while also preventing noise caused bythe vibration of the entire pump.

What is claimed is:
 1. An immersed pump comprising: a body frame; amotor mounted at an upper end of the body frame; a pump housing mountedat a lower end of said body frame and formed entirely of a plurality ofcylindrical housing members coupled together in a vertical direction,the housing members including lower housing members and upper housingmembers which are positioned above the lower housing members; a rotatingshaft extending from said motor through an inside of the body frame tosaid pump housing; at least one impeller attached to the rotating shaftin the pump housing and provided in respective lower housing members; atleast one suction port provided on respective upper housing members; anejection port provided at a lower end of the pump housing; and the atleast one impeller being rotated by said motor to draw a liquid in atank from the at least one suction port into the pump housing and ejectthe liquid from the ejection port.
 2. An immersed pump according claim1, wherein said ejection port is provided on an extension of an axis ofsaid rotating shaft, and wherein a joint that is directly joined with anejection hole provided at a bottom of the tank is mounted in theejection port.
 3. An immersed pump according to claim 1, wherein saidplurality of cylindrical housing members are detachably coupledtogether, and wherein each of said at least one impeller is removablyattached to said rotating shaft.
 4. An immersed pump according to claim1, wherein said suction port is formed at the lower end of the bodyframe.